1. Field of the Invention
The present invention relates to a suspension device including two telescopic elements.
2. Description of the Related Art
Suspension devices installed on a vehicle equipped with a vehicle body frame that is tilted in a left-right direction when the vehicle is cornering and two front wheels that are arranged in the left-right direction of the vehicle body frame are known (for example, refer to U.S. Pat. No. 4,351,410; Chinese Unexamined Patent Publication No. 101774414A; and WO 2012/007819).
The vehicle, equipped with the tiltable vehicle body frame and the two front wheels, has a link mechanism. The link mechanism includes cross members. The link mechanism also includes aright side rod for supporting a right end portion of an upper cross member and a left side rod for supporting a left end portion of the cross member. Intermediate portions of the cross members are supported via the vehicle body frame in front of a steering shaft. The cross members are supported on the vehicle body frame so as to be rotatable about an axis extending substantially in front-rear direction of the vehicle body frame. The cross members are rotated with respect to the vehicle body frame associated with the tilting of the vehicle body frame, whereby the relative positions of the two front wheels in up-down direction of the vehicle body frame are changed. In an upright state of the vehicle body frame, the cross members are provided above the two front wheels in the up-down direction of the vehicle body frame.
The vehicle equipped with the tiltable vehicle body frame and the two front wheels includes a right suspension device for supporting the right front wheel so that the right front wheel is movable in the up-down direction of the vehicle body frame and a left suspension device for supporting the left front wheel so that the left front wheel is movable in the up-down direction of the vehicle body frame. The right suspension device is supported on the right side rod so as to be rotatable about the axis of the right side rod. The left suspension device is supported on the left side rod so as to be rotatable about the axis of the left side rod. The vehicle described in each of U.S. Pat. No. 4,351,410 and Chinese Unexamined Patent Publication No. 101774414A is further equipped with a handle, a steering shaft and a rotation transmission mechanism. The handle is secured to the steering shaft. The steering shaft is supported on the vehicle body frame so as to be rotatable with respect thereto. When the handle is turned, the steering shaft is also rotated. The rotation transmission mechanism transmits the rotation of the steering shaft to the right suspension device and the left suspension device.
Numerous components to be installed on the vehicle are disposed on the right suspension device and the left suspension device and therearound. The components are brake components, such as brake discs and brake calipers, sensors, fenders, covers, wheels.
In U.S. Pat. No. 4,351,410, as viewed from the front side of a vehicle in the upright state of the vehicle body frame thereof, a right suspension device includes a right-right telescopic element positioned on the right of a right front wheel and a right-left telescopic element positioned on the left of the right front wheel in the left-right direction of the vehicle body frame. As viewed from the front side of the vehicle in the upright state of the vehicle body frame, a left suspension device includes a left-right telescopic element positioned on the right of a left front wheel and a left-left telescopic element positioned on the left of the left front wheel in the left-right direction of the vehicle body frame. Each telescopic element includes an outer portion and an inner portion of which at least a portion is inserted into the outer portion. The extension/contraction of the telescopic element is the relative movement of the inner portion with respect to the outer portion. When the right front wheel passes through a convex portion of the road surface, the right-right telescopic element and the right-left telescopic element extend and contract, and the right front wheel is displaced upward. At this time, the right-right telescopic element and the right-left telescopic element have rigidity capable of enduring the load applied from the road surface to the front wheel supported thereby. When the left front wheel passes through the convex portion of the road surface, the left-right telescopic element and the left-left telescopic element extend and contract, and the left front wheel is displaced upward. At this time, the left-right telescopic element and the left-left telescopic element have rigidity capable of enduring the load applied from the road surface to the front wheel supported thereby. As described above, the telescopic elements are required to have rigidity sufficient to endure the load applied from the road surface to the front wheel supported thereby. The vehicle disclosed in U.S. Pat. No. 4,351,410 has a configuration capable of sufficiently enduring the loads applied from the road surface to the right front wheel and the left front wheel by using the four telescopic elements.
However, in U.S. Pat. No. 4,351,410, as viewed from the front side of the vehicle in the upright state of the vehicle body frame, six members, that is, the right-right telescopic element, the right front wheel, the right-left telescopic element, the left-right telescopic element, the left front wheel and the left-left telescopic element, are arranged in the left-right direction of the vehicle body frame. Hence, the vehicle disclosed in U.S. Pat. No. 4,351,410 is large in the left-right direction of the vehicle body frame. As a result, the vehicle disclosed in U.S. Pat. No. 4,351,410 is large in the left-right direction because the six members are arranged in the left-right direction of the vehicle body frame although the vehicle can sufficiently endure the load applied from the road surface to the right front wheel and the left front wheel using the four telescopic elements.
For the purpose of downsizing a vehicle in the left-right direction of the vehicle body frame thereof, a vehicle has been proposed in each of Chinese Unexamined Patent Publication No. 101774414A and WO 2012/007819 in which, of the four telescopic elements thereof, the right-right telescopic element disposed on the right of the right front wheel and the left-left telescopic element disposed on the left of the left front wheel are moved to the space between the right front wheel and the left front wheel. The right suspension device according to each of Chinese Unexamined Patent Publication No. 101774414A and WO 2012/007819 includes a right-front telescopic element and a right-rear telescopic element disposed on the left of the right front wheel. In addition, the left suspension device includes a left-front telescopic element and a left-rear telescopic element disposed on the right of the left front wheel. The vehicle according to each of Chinese Unexamined Patent Publication No. 101774414A and WO 2012/007819 includes four telescopic elements as well as U.S. Pat. No. 4,351,410. As a result, the vehicle according each of Chinese Unexamined Patent Publication No. 101774414A and WO 2012/007819 can sufficiently endure the load applied from the road surface to the right front wheel and the left front wheel.
However, in a vehicle equipped with the tiltable vehicle body frame and the two front wheels, the right front wheel and the right suspension device are rotated about the axis of the right side rod associated with the turn of the handle. The left front wheel and the left suspension device are rotated about the axis of the left side rod associated with the turn of the handle. Furthermore, in the vehicle equipped with the tiltable vehicle body frame and the two front wheels, the relative positions of the right front wheel and the left front wheel in the up-down direction of the vehicle body frame are changed in association with the tilting of the vehicle body frame in the left-right direction. Similarly, the relative positions of the right suspension device and the left suspension device in the up-down direction are also changed. In addition, at this time, the distance between the right front wheel and the left front wheel becomes small in the left-right direction of the vehicle body frame. Similarly, the distance between the right suspension device and the left suspension device also becomes small.
The vehicle according to each of Chinese Unexamined Patent Publication No. 101774414A and WO 2012/007819 is equipped with four telescopic elements between the right front wheel and the left front wheel. Hence, in particular, when the handle is turned while the vehicle body frame is tilted in the left-right direction, the two telescopic elements of the right suspension device rotating about the axis of the right side rod may interfere with the left front wheel or the two telescopic elements of the left suspension device rotating about the axis of the left side rod. Similarly, when the handle is turned while the vehicle body frame is tilted in the left-right direction, the two telescopic elements of the left suspension device rotating about the axis of the left side rod may interfere with the right front wheel or the two telescopic elements of the right suspension device rotating about the axis of the right side rod. For avoiding such interference, it is necessary to increase the distance between the two telescopic elements of the right suspension device and the two telescopic elements of the left suspension device. Furthermore, it is also necessary to increase the distance between the right front wheel and the left front wheel. Hence, in the vehicle according to each of Chinese Unexamined Patent Publication No. 101774414A and WO 2012/007819, although downsizing of the vehicle is achieved by moving the telescopic elements provided on the right of the right front wheel and on the left of the left front wheel to the space between the right front wheel and the left front wheel, the downsizing in the left-right direction is not sufficient because the distance between the right front wheel and the left front wheel becomes large.